1H NMR (400 MHz, CDCl3) δ 8.12 (d, J = 8.1 Hz, 2H), 7.79 (d, J = 8.1 Hz, 2H), 5.99 (s, 1H), 5.69 (s, 1H), 3.96 (s, 3H), 3.54 (s, 2H), 2.14 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 196.3, 166.2, 143.7, 141.2, 133.2, 129.5, 129.2, 127.0, 52.4, 34.9, 15.6. HRMS (EI): calcd for C13H14O3S: 250.0664; found: 250.0661.